1. Field of the Invention
The present invention generally relates to a coordinate input apparatus, and particularly relates to a coordinate input apparatus for use in a character input portion of a word processor, in a coordinate input portion of a personal computer, a CAD terminal equipment, or the like, in a slip hand-written character input portion of a bank terminal equipment or the like, and so on.
2. DESCRIPTION OF THE PRIOR ART
Conventionally, a coordinate input apparatus or a character input apparatus, in which a display unit using a liquid crystal and a coordinate input tablet are integrally combined with each other, has been commercialized as an apparatus having a function of coordinate input for indicating coordinates on a displayed picture screen.
In a display unit using a liquid crystal, a CRT, or the like, display is generated by changing the state of the liquid crystal from a transmitting state to a reflecting state to cause the liquid crystal to reflect light, or by causing a fluorescent material inside the display surface of the CRT to be luminous. Thick glass is generally used to protect the surface of the display. Accordingly, when a display is actually effected at a designated position on the display surface in response to designation of coordinates by means of coordinate indicating means, such as a pen having a coordinate designating function, a displacement occurs between the actually displayed position designated by means of the coordinate indicating means and the displayed position recognized by a user through the thick protection glass. Accordingly, the user is required to perform coordinate designation while taking such a displacement into consideration. Thus, there has been an inconvenience in the practical use of such a device. Examples of such a conventional coordinate input apparatus includes those disclosed in Japanese Patent Unexamined Publication No. 56-36738, and so on.